The density of Wi-Fi Access Points (APs) has increased rapidly in urban downtowns and enterprise and campus networks. In most scenarios, a Wi-Fi client has the choice to associate with more than one available AP. Therefore, it is increasingly common to find physically nearby Wi-Fi clients that are associated with different APs.
A number of applications can benefit from the ability to send and receive information from nearby clients. For example, clients can perform better AP selection if they have knowledge about the performance of clients associated to neighboring APs. Applications such as “buddies near me” can discover clients that are nearby but associated to another AP. Similarly, geocasting based applications can reach out to more clients in the same region than being limited to only one wireless network.
Existing schemes to enable these applications, however, require significant infrastructure changes or extensive manual profiling. For example, 802.11k modifies the APs and client drivers for better AP selection. BeaconStuffing modifies the APs to send information about load on its network. Further, existing implementations of “buddies near me”, such as AOL's buddy list, require extensive wardriving.
Further, current practices do not support, neighborcast, using which nearby clients can communicate with each other even when they are associated to different APs and do not leverage multicast to achieve this functionality. In a contemplated scheme, each AP can be assigned a globally unique multicast group ID, and a Wi-Fi client with an IP address joins the multicast group corresponding to all APs around it. Multicast functionality using either IP multicast, Application Level Multicast or a web-server based scheme using RSS feeds can also be implemented.
Unlike existing practices, neighborcast does not require any modifications to the APs or kernel-level software changes at the clients. Furthermore, by using IP multicast or Application Level Multicast, neighborcast traffic generated by a Wi-Fi client is local, i.e., propagates only to nearby APs. Neighborcast, when deployed, can be more scalable than a completely centralized publish/subscribe based scheme.
From the foregoing it is appreciated that there exists a need to overcome the shortcomings of existing practices as it pertains to wireless communications network to enable neighborcast.